NOOB Dumb flash question

wyogirl · Jul 5, 2013

Hello there--
I'm trying to learn off camera flash, and so far failing. I have a YN speedlight with TTL. I had it on a stand with a white shoot through umbrella about 5 feet from my model who was in shade at the east side of a building during evening golden hour. I did not have my flash on manual, and I was using radio a receiver/transceiver. I either got way over exposed images or just not good ones (bad description I know).

As I am VERY new to off camera flash can you help me. Do I need to work in manual for this to work? Obviously I'm doing something wrong. I read the strobist blog on off camera lighting, but yeah, my first attempt wasn't all sunshine and roses. I'm sure practice is in order, but I thought someone might have tips.

Also, I don't understand manual flash. With the zoom and the power.... is there something I can read that explains that?

tirediron · Jul 5, 2013

The best OCF resource of which I am aware! Start with lighting 101.

wyogirl · Jul 5, 2013

Thanks-- I have read that and I'll certainly read it again.

Do you have to use manual flash for off camera?

tirediron · Jul 5, 2013

No, but it's much, much easier.

cgipson1 · Jul 5, 2013

TTL is a bit flaky, and the exposures can vary quite a bit. A lot depends on how you are metering.

Third party flashes are less accurate then OEM flashes, because they have to backwards engineer the TTL for the flash (not having access to the original OEM code), and also just due to build quality. Throw in wireless (that may or may not be transferring all of the data) and you have too many variables.

Manual will be much more accurate, since it does not vary with metering differences. Once you have it set for a certain subject / distance... it stays there (and as long as subject distance stays the same... it will be the same).

I have found that TTL using OEM (Nikon) flashes, and using Pocket Wizard TT5 transceivers (TTL capable) is much more accurate than any of the third party stuff (albeit much more expensive)

wyogirl · Jul 5, 2013

Thanks... I'll try manual next time. I kind of had a feeling that there might have been lost info with the wireless set up. My TTL works pretty good when in hot shoe though. I'm going to be doing a lot of studying!

Derrel · Jul 5, 2013

You need to learn about Guide Number. It is best though of as a "Power Index" for the flash. Since this is the USA, I would use the Guide Number (GN) specified in Feet, at ISO 100. Not sure which flash you have, or what its GN is. Set the flash a specific distance from the umbrella, say, 7/8 of the way back on the umbrella shaft. Use a specific flash zoom setting, such as 35mm or "wide" zoom. Set flash to Full, Manual Power. Assuming a GN of 110 in Feet at ISO 100, that means at 10 feet, the f/stop needed will be f/11. From: 110 divided by 10 feet, equals 11, with 11 being the needed f/stop for proper exposure.

If you want to use the flash as FILL-in light against the setting sun, half power flash might be more appropriate, and might look better with an orange gel fitted to the flash, so the light coming thru the umbrella is not so doggone "white".

You can tie a string to the umbrella tip, and with some experimentation, determine exactly how far the string must be extended to help you measure out the exact distance for f/4,f/5.6, f/8,f/11,and f/16, with the flash set 7/8 of the way back on the shaft, at 35mm zoom, and at FULL manual power.